Wood-based doors may be either solid wood or may be made of a wood-based composite. Composite wood doors may comprise a supportive frame that is at least partially covered with a wood-containing water-resistant layer known as a molded skin or a door skin. In some cases, the composite door may have an inner core that is filled with a cellulosic or synthetic polymer material.
To assemble a composite door, a door frame, usually including at least two horizontal pieces called rails and at least two vertical pieces called stiles, may be assembled using either glue or fasteners to hold the frame together. The frame may then be placed on top of a door skin, such that the side of the door skin facing the frame will become the inside of the door, and the other side of the door skin will become one of the outside surfaces of the door. Next, a material to form the inner core of the door may be applied to the areas of the door bounded by the frame and door skin. Various core materials, such as wood block, particleboard, or medium density fiberboard may be used for the core. Also, combinations of these materials may be used to form the core. Subsequently, a second door skin may be placed on top of the frame and core to make the other outside surface of the door.
Manufacturers of composite doors strive to produce composite doors of high quality that closely resemble a solid wood door. There is also a need, however, to reduce the cost of manufacturing composite doors. Additionally, as manufacturing doors can be a physically demanding and labor-intensive endeavor, there is a need to strive to improve the utilization of the labor force. Yet another consideration is the need to reduce waste in the production process and to minimize the amount of raw materials used. Thus, there is a continuing need to provide processes and systems to optimize production of composite doors.